Method for manufacturing semiconductor device

ABSTRACT

It is an object of the invention to provide a peeling method which does not damage a peeling layer, and to perform peeling not only a peeling layer having a small-size area but also an entire peeling layer having a large-size area with a preferable yield. In the invention, after pasting a fixing substrate, a part of a glass substrate is removed by scribing or performing laser irradiation on the glass substrate which leads to providing a trigger. Then, peeling is performed with a preferable yield by performing peeling from the removed part. In addition, a crack is prevented by covering the entire face except for a connection portion of a terminal electrode (including a periphery region of the terminal electrode) with a resin.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a semiconductor device having a circuitincluding a thin film transistor (hereinafter referred to as a TFT), andto a method for manufacturing the same. For example, the inventionrelates to an electronic device on which an electro-optical devicetypified by a liquid crystal display panel or a light emitting displaydevice having an organic light emitting element is mounted as itscomponent.

In this specification, the term “semiconductor device” refers to adevice in general that utilizes semiconductor characteristics tofunction, and electro-optical devices, semiconductor circuits andelectronic devices are all included in the semiconductor device.

2. Description of the Related Art

In recent years, a technique for forming a thin film transistor (a TFT)by using a semiconductor thin film (thickness is approximately fromseveral nm to several hundreds nm) formed over a substrate having aninsulating surface has drawn attention. The thin film transistor hasgained a wide application in electronic devices such as an IC and anelectro-optical device, and particularly, development of a TFT as aswitching element for an image display device has been hurriedly carriedout.

As for applications utilizing such an image display device, a variety ofapplications is expected. The utilization for a portable device hasdrawn attention, in particular. Although a glass substrate and a quartzsubstrate are widely utilized at present, there is a disadvantage ofbeing easily cracked and heavy. Moreover, a glass substrate and a quartzsubstrate are difficult to be made larger on the basis ofmass-production, and these are not suitable for that. Therefore, forminga TFT element over a substrate having flexibility, typically, over aflexible plastic film has been attempted.

However, since the heat resistance of a plastic film is low, it cannothelp lowering the highest temperature of a process. As a result, a TFTwhich has not so excellent electric characteristics compared with thoseformed over a glass substrates is formed at present. Therefore, a liquidcrystal display device and a light emitting element having a highperformance using a plastic film have not been realized yet.

Moreover, a method for peeling a peeling layer existing over a substratewith a separation layer therebetween from the substrate has been alreadyproposed. For example, techniques described in Japanese Patent Laid-OpenNo. Hei 10-125929 and Japanese Patent Laid-Open No. Hei 10-125931 aretechniques that a separation layer including an amorphous silicon (or apolysilicon) is provided, laser light is radiated by being transmittedthrough the substrate, and makes hydrogen contained in the amorphoussilicon released, thereby generating a space-gap to separate thesubstrate. In addition, there is also a description in Japanese PatentLaid-Open No. Hei 10-125930 that by utilizing this technique, a liquidcrystal display device is completed by pasting a peeling layer (in thegazette, referred to as a transferring layer) to a plastic film.

However, in the above-mentioned method, it is essential to use asubstrate having high light-transmitting properties, and fortransmitting light through the substrate and further, for the purpose ofgiving sufficient energy for releasing hydrogen contained in theamorphous silicon, the irradiation of laser light having comparativelylarge energy to the entire surface is necessary. Consequently, there isa problem that the peeling layer is damaged. Moreover, in theabove-mentioned method, in the case when an element is manufactured overa separation layer, if heat treatment at a high temperature or the likeis performed in the process for manufacturing the element, hydrogencontained in the separation layer is dispersed and reduced. In thatcase, even if the laser light is radiated on the separation layer, thereis a possibility that the peeling is not sufficiently performed.Therefore, in order to maintain the amount of hydrogen contained in theseparation layer, a problem that the processes after the separationlayer formation are limited occurs. Moreover, in the above-mentionedgazette, there is also a description that, a light-shielding layer or areflection layer is provided in order to prevent a damage to the peelinglayer. However, in this case, it is difficult to manufacture atransmissive type liquid crystal display device. In addition, by theabove-mentioned method, it is difficult to peel a peeling layer having alarge area.

Accordingly, the applicant proposes a peeling technique and atransferring technique described in Japanese Patent Laid-Open No.2003-174153.

BRIEF SUMMARY OF THE INVENTION

It is an object of the present invention to provide a method for peelingwithout damaging a peeling layer, and to peel not only a peeling layerhaving a small area but also a peeling layer having a large areaentirely with a preferable yield.

In the invention, when a metal layer is formed over a substrate and anoxide layer is laminated thereover, a metal oxide layer caused by themetal layer is formed at the interface between the metal layer and theoxide layer. A peeling method in which peeling is performed in a laterstep by using the metal oxide layer is used.

Specifically, a tungsten film (or an alloy film such as a tungstennitride film) is formed over a glass substrate by sputtering, and asilicon oxide film is laminated by sputtering. When the silicon oxidefilm is formed by sputtering, a tungsten oxide layer in an amorphousstate is formed. Then, the tungsten oxide layer is crystallized byforming an element such as a TFT over the silicon oxide film and byperforming heat treatment of at least 400° C. in the element formationprocess. When physical force is applied, peeling occurs inside thetungsten oxide layer or at the interface. The peeling layer (includingan element such as a TFT) peeled in this way is transferred to a plasticsubstrate.

It is significant to provide a trigger in order to make a peelingphenomenon easily occur before peeling. In view of this, by performingpretreatment which selectively (partially) weakens adhesion, a peelingdefect disappears resulting in further improvement in the yield.

In the invention, after pasting a fixing substrate, a part of the glasssubstrate is removed by scribing or performing laser irradiation on theglass substrate, which leads to providing a trigger.

As laser light, a gas laser such as an excimer laser, a CO₂ laser, or anargon laser; a solid-state laser such as a glass laser, a ruby laser, analexandrite laser, or Ti: sapphire laser; a solid-state laser using acrystal in which Nd, Tm and Ho are doped in a crystal such as YAG, YVO₄,YLF or YAlO₃; or a semiconductor laser may be used. The form of laseroscillation may be either continuous oscillation or pulse oscillation,and the shape of the laser beam may be any of a linear, rectangular,circular or elliptical shape. Moreover, the wavelength to be used may beany one of a fundamental wave, the second harmonic, or the thirdharmonic, and it can be appropriately selected by the practitioner.Further, the scanning method may be carried out in the verticaldirection, the transverse direction, or diagonal direction and further,may be reciprocated.

One feature of the invention is that peeling is performed from a thusremoved part. It is made easier to push a wedge for peeling between twofixing substrates being pasted each other, by removing a part of theglass substrate.

When a comparatively large substrate is used, gang printing isperformed, which requires a plurality of alignment markers used foraligning a substrate or the like. An etching hole is used as analignment marker. The etching hole is an opening having a glasssubstrate as its bottom surface and even an interlayer insulating filmand a tungsten film are removed. However, the alignment markerssometimes cause a peeling defect. When a part where an alignment markeris provided and a circuit are aligned in the peeling direction, if apeeling defect occurs in the alignment marker part, the circuit which isin an extension of the peeling direction might be damaged.

Consequently, in the invention, alignment markers are arranged only inthe circumference of a substrate, and the alignment markers are removedas a part of a glass substrate before peeling. It causes no problem evenif the alignment markers are removed since the alignment markers are notnecessary in a later step after a TFT is manufactured. In addition,peeling is performed in a direction where a plurality of alignmentmarkers is arranged, since a peeling defect and the arrangement ofalignment markers are related to each other. The location of thealignment markers and the arrangement of circuits are appropriately setin accordance with the direction in which peeling is performed.

When a device formed over a flexible film is mounted, a terminalelectrode is conducted by pasting an FPC with pressure-bonding. In thepressure-bonding step, a crack is likely to occur since a wiring formedover the film (a wiring connected to the terminal electrode) is damaged.It is assumed that the crack is generated by deformation due toapplication of pressure since the film has flexibility. When the crackis large, there is a possibility to cause disconnection.

Therefore, one feature of the invention is to cover the entire faceexcept for a connection portion of a terminal electrode (including acircumference of the terminal electrode) with a resin to prevent a crackfrom occurring.

A method for manufacturing a semiconductor device according to aconfiguration of the invention disclosed in this specification comprisesthe steps of: forming a peeling layer containing an element over a firstsubstrate; applying an organic resin film which can be dissolved in asolvent over the peeling layer containing an element; pasting a firsttwo-sided tape over the organic resin film; cutting off and removing apart of the first substrate; pasting a second substrate to the firsttwo-sided tape; pasting a third substrate under the first substrate witha second two-sided tape; performing peeling to separate the firstsubstrate, the second two-sided tape, and the third substrate from thepeeling layer; pasting a fourth substrate to the peeling layer with anadhesive material.

A method for manufacturing a semiconductor device according to anotherconfiguration of the invention comprises the steps of: forming a peelinglayer containing an element and an alignment marker over a firstsubstrate; forming an organic resin film which can be dissolved in asolvent over the peeling layer containing an element; pasting a firsttwo-sided tape over the organic resin film;cutting off and removing apart of the first substrate which is overlapped with the alignmentmarker; pasting a second substrate to the first two-sided tape; pastinga third substrate under the first substrate with a second two-sided tape; performing peeling to separate the first substrate, the secondtwo-sided tape, and the third substrate from the peeling layer; pastinga fourth substrate to the peeling layer with an adhesive material.

One feature of each above-mentioned configuration is that the secondsubstrate and the third substrate have higher rigidity than that of thefirst substrate, and the fourth substrate is a film substrate.

In each of the above-mentioned configurations, peeling is performed bypasting the third substrate to the first substrate considering the casewhen the rigidity and the like are not enough when the first substrateis peeled. However, when the rigidity and the like are enough, it isunnecessary to paste the third substrate.

One feature of each above-mentioned configuration is that the peeling isperformed from a part where the part of the first substrate is cut offand removed.

One feature of each above-mentioned configuration is that furthercomprising steps of: removing the second substrate; removing the firsttwo-sided tape; and removing the organic resin film by dissolving with asolvent.

One feature of each above-mentioned configuration is that the element isa TFT element.

A method for manufacturing a semiconductor device according to anotherconfiguration of the invention comprises the steps of: forming a peelinglayer containing an element over a first substrate; forming an organicresin film which dissolves in a solvent over the peeling layercontaining an element; pasting a two-sided tape over the organic resinfilm;

-   -   cutting off and removing a part of the first substrate; pasting        a second substrate to the two-sided tape; performing peeling        from the part where a part of the first substrate is cut off and        removed to separate the first substrate from the peeling layer        containing an element; pasting a third substrate to the peeling        layer containing an element with an adhesive material;    -   removing the second substrate; removing the two-sided tape; and        removing the organic resin film by dissolving with a solvent.

One feature of the above-mentioned configuration is that the secondsubstrate has higher rigidity than that of the first substrate, and thethird substrate is a film substrate.

A method for manufacturing a semiconductor device according to anotherconfiguration of the invention comprises the steps of: forming a peelinglayer containing an element and a terminal electrode over a firstsubstrate; peeling the peeling layer containing an element and aterminal electrode from the first substrate; pasting a second substrateto the peeling layer containing an element and a terminal electrode withan adhesive material; and pressure-bonding an FPC to a terminalelectrode in which a circumference is covered with a resin.

One feature of the above-mentioned configuration is that the firstsubstrate is a glass substrate and the second substrate is a filmsubstrate.

In each of the above-mentioned configurations, the step of peeling thepeeling layer from the first substrate is not particularly limited, anda known method may be used. Above all, with the use of a peelingtechnique and a transferring technique described in Japanese PatentLaid-Open No. 2003-174153, a TFT having high mobility which can beobtained by heat treatment of 500° C. or more over a glass substrate canbe transferred to a plastic substrate with a preferable yield. Thepeeling technique and the transferring technique described in JapanesePatent Laid-Open No. 2003-174153 are a peeling method in which a metallayer is formed over a substrate, a metal oxide layer of the metal layeris formed at the interface between the metal layer and an oxide layerwhen laminate the oxide layer over the metal layer, and peeling isperformed in a later step with the use of the metal oxide layer.

Specifically, a tungsten film is formed by sputtering over a glasssubstrate, and a silicon oxide film is laminated by sputtering. Atungsten oxide layer in an amorphous state is formed when the siliconoxide film is formed by sputtering. Then, an element such as a TFT isformed over the silicon oxide film. The tungsten oxide layer iscrystallized by performing heat treatment of 400° C. or more in theelement formation process. When physical force is added, peeling occursinside or at the interface of the tungsten oxide layer. The peelinglayer peeled in this way (including an element such as a TFT) istransferred to a plastic substrate.

In each of the above-mentioned configurations, the peeling layer is alayer including a semiconductor integrated circuit having variouselements typified by a TFT (a thin film diode; or a photoelectrictransducer element, a silicon resistance element, or a sensor element(typically, a pressure-sensitive fingerprint sensor with the use ofpolysilicon) including a PIN junction of silicon). The peeling layer maybe also called as a separation layer.

It is possible to apply the invention regardless of a TFT structure, andfor example, it is possible to use a top gate type TFT, a bottom gatetype (an inverse stagger type) TFT, or a forward stagger type TFT. Inaddition, the invention is not limited to a single gate structure TFT,and a multi-gate type TFT having a plurality of channel formationregions, for example, a double gate type TFT may be also used.

As an active layer of the TFT, an amorphous semiconductor film, asemiconductor film containing a crystal structure, a compoundsemiconductor film containing an amorphous structure can beappropriately used. Further, a semi-amorphous semiconductor film whichis a semiconductor having an intermediate structure of an amorphousstructure and a crystal structure (including single crystal andpolycrystal), and a tertiary state which is stable energetically, andincluding a crystalline region having a short distance order and latticedistortion (also referred to as a microcrystal semiconductor film) canbe used as the active layer of the TFT. In the semi-amorphoussemiconductor film, a crystal grain having a grain diameter of from 0.5run to 20 nm is included in at least one region of the film, and in theRaman spectrum shifts to the lower side of wave number of 520 cm⁻¹. Inaddition, in the semi-amorphous semiconductor film, a diffraction peakof (111) and (220) derived from a Si crystal lattice is observed inx-ray diffraction. The semi-amorphous semiconductor film includeshydrogen or halogen of at least 1 atom % as a neutralizer of anuncombined hand (a dangling bond). The semi-amorphous semiconductor filmis manufactured by performing glow discharging decomposition (plasmaCVD) of a silicide gas. As the silicide gas, SiH₄, additionally, Si₂H₆,SiH₂Cl₂, SiHCl₃, SiCl₄, SiF₄, or the like can be used. The silicide gasmay be diluted with H₂, or H₂ and one or more of rare gas elements: He,Ar, Kr, and Ne. Dilution ratio is within the range of from 2 times to1000 times. Pressure is roughly within the range of from 0.1 Pa to 133Pa; a power frequency, from 1 MHz to 120 MHz, preferably from 13 MHz to60 MH; and a substrate heating temperature, at most 300° C., preferablyfrom 100° C. to 250° C. An atmospheric constitution impurity such asoxygen, nitrogen or carbon as an impurity element within a film ispreferably at most 1×10²⁰ cm⁻³, in particular, oxygen concentration isat most 5×10¹⁹ atoms/cm³, preferably, at most 1×10¹⁹ atoms/cm³. Notethat electric field-effect mobility μ of a TFT in using a semi-amorphousfilm as an active layer is from 1 cm²/Vsec to 10 cm²/Vsec.

According to the invention, peeling can be performed with a preferableyield on the entire face of a peeling layer having a large area.

BRIEF DESCRIPTION OF THE DRAWING

FIGS. 1A to 1F are cross-sectional views showing manufacturing steps ofthe invention (Embodiment Mode 1).

FIGS. 2A to 2E are cross-sectional views showing manufacturing steps ofthe invention (Embodiment Mode 1).

FIGS. 3A and 3B are top views showing peeling steps of the presentinvention (Embodiment Mode 1).

FIGS. 4A to 4C are cross-sectional views and a top view showingmanufacturing steps of the invention (Embodiment Mode 2).

FIGS. 5A and 5B are cross-sectional views showing Embodiment 1.

FIG. 6 is a photograph of a surface and a cross-section aftertransferring (Embodiment 1).

FIG. 7 is an SEM picture of a cross-section of a TFT (Embodiment 1).

FIG. 8 is a photograph of a plurality of CPUs provided over a filmsubstrate (Embodiment 1).

FIG. 9 is a photograph of a CPU in one chip provided over a plasticsubstrate (Embodiment 1).

FIG. 10 is a block diagram (Embodiment 1).

FIG. 11 shows current characteristics of a TFT (Embodiment 1).

FIG. 12 shows an evaluation result of a CPU (Embodiment 1).

FIGS. 13A to 13J are diagrams showing manufacturing steps of a lightemitting device (Embodiment 2).

FIGS. 14A to 14C are diagrams showing examples of electronic devices(Embodiment 3).

DETAILED DESCRIPTION OF THE INVENTION

Embodiment modes of the present invention are described hereinafter.

EMBODIMENT MODE 1

Here, a method for peeling with the use of a metal film and a siliconoxide film is used.

Initially, a peeling layer 103 which includes a semiconductor integratedcircuit (here, a CPU), a terminal electrode (not shown), and analignment marker (not shown) is formed over a first substrate 100.

A metal film 101 a, here, a tungsten film (a film thickness of from 10nm to 200 nm, preferably from 30 nm to 75 nm) is formed by sputtering,and an oxide film 102, here, a silicon oxide film (a film thickness offrom 150 nm to 200 nm) is further laminated over the substrate withoutbeing exposed to the atmospheric air by sputtering. The film thicknessof the oxide film 102 is desirably twice that of the metal film. At thetime of laminating, a metal oxide film (a tungsten oxide film) in anamorphous state is formed with a thickness of from 2 nm to 5 nm betweenthe metal film 101 a and the silicon oxide film 102. In peeling in alater step, separation occurs inside the tungsten oxide film, at theinterface between the tungsten oxide film and the silicon oxide film, orat the interface between the tungsten oxide film and the tungsten film.

The tungsten film, the tungsten oxide film and the silicon oxide filmare formed also over an end face of the substrate with the use ofsputtering; therefore, it is preferable to remove these filmsselectively by O₂ ashing or the like.

Subsequently, a silicon oxynitride film (a film thickness of 100 nm)(not shown) which serves as a base insulating film is formed by PCVD,and an amorphous silicon film containing hydrogen (a film thickness of100 nm) is further laminated without being exposed to the atmosphericair.

Thereafter, the amorphous silicon film is crystallized by using a knowntechnique (solid-phase growth, laser crystallization, crystallizationusing catalytic metal, or the like), and an element using a TFT having apolysilicon film as an active layer is formed. Here, the polysiliconfilm is obtained with crystallization using catalytic metal. A nickelacetate salt solution containing nickel of 10 ppm by weight is appliedwith a spinner. A nickel element can be sprayed over the entire surfaceby sputtering instead of spin coating. Then, heat treatment is carriedout to crystallize the amorphous silicon film and to form asemiconductor film having a crystal structure (here, a polysiliconlayer). In this embodiment mode, the silicon film having a crystalstructure is obtained by performing heat treatment for crystallization(at 550° C. for 4 hours) after another heat treatment (at 500° C. forone hour).

Another crystallization method may be a method for obtaining apolysilicon film by irradiating a polysilicon film which is obtained byheating the amorphous silicon film after adding a metal element whichserves as a catalyst, with continuous oscillation laser light; a methodfor obtaining a polysilicon film by irradiating the amorphous siliconfilm with continuous oscillation laser light; a method for obtaining apolysilicon film by irradiating a polysilicon film which is obtained byheating the amorphous silicon with continuous oscillation laser light;or a method for obtaining a polysilicon film by irradiating apolysilicon film which is obtained by heating the amorphous silicon filmafter adding a metal element which serves as a catalyst, with continuousoscillation laser light.

The amorphous silicon film contains hydrogen. In the case of forming apolysilicon film by heating, when heat treatment of 410° C. or more isperformed for crystallization, hydrogen can be diffused as well asforming the polysilicon film. The metal oxide film in an amorphous stateis crystallized by heat treatment of 410° C. or more; therefore, a metaloxide film 101 b having a crystal structure can be obtained.Accordingly, the heat treatment of 410° C. or more makes it possible toform the metal oxide film having a crystal structure; therefore,hydrogen is diffused. After the heat treatment of 410° C. or more isfinished, the separation inside of the tungsten oxide film, or at theinterface between the tungsten oxide film and the silicon oxide film, orat the interface between the tungsten oxide film and the tungsten filmcan be achieved with relatively small force (for example, human hands,wind pressure of a gas blown from a nozzle, ultrasonic waves, or thelike). Note that, when heat treatment is performed at a temperature atwhich the metal oxide film having a crystal structure can be obtained,the thickness thereof is thinned to some extent.

An oxide film on the surface of the silicon film having a crystalstructure is removed with diluted hydrofluoric acid or the like. Then inorder to enhance the crystallization rate and to repair a defectremaining in a crystal grain, the silicon film is irradiated with laserlight (XeCl with the wavelength of 308 nm) in the atmospheric air or inan oxygen atmosphere.

A barrier layer formed of an oxide film formed by treating the surfacewith ozone water for 120 seconds in addition to the oxide film formed bythe laser light irradiation, is formed with a thickness of from 1 nm to5 nm in total. The barrier layer is formed to remove nickel which isadded for crystallization from inside of the film. Before forming thebarrier layer, the oxide film formed by laser light irradiation may beremoved.

Over the barrier layer, an amorphous silicon film containing an argonelement is formed to have a thickness of 10 nm to 400 nm, in thisembodiment mode, 100 nm by sputtering or PCVD to serve as a getteringsite.

Then, a furnace heated at 650° C. is used for heat treatment for 3minutes for gettering to reduce the nickel concentration in thesemiconductor film having a crystal structure. A lamp annealingapparatus may be substituted for the furnace.

Subsequently, the amorphous silicon film containing an argon element,which is the gettering site, is selectively removed by using the barrierlayer as an etching stopper, and then, the barrier layer is selectivelyremoved with diluted hydrofluoric acid. Note that there is a tendencythat nickel is likely to move to a region having a high oxygenconcentration in gettering, and thus, it is desirable that the barrierlayer formed of the oxide film is removed after gettering.

In the case of not performing crystallization by using a catalyticelement, the above-mentioned steps such as the formation of the barrierlayer, the formation of the gettering site, the heat treatment forgettering, the removal of the gettering site, and the removal of thebarrier layer are not necessary.

Then, after a thin oxide film is formed from ozone water on the surfaceof the obtained silicon film having a crystal structure (also referredto as a polysilicon film), a mask made from a resist is formed, and anetching treatment is conducted thereto to obtain a desired shape,thereby forming the island-like semiconductor layers separated from oneanother. After forming the semiconductor layers, the mask made from aresist is removed.

Subsequently, a gate insulating film which covers the semiconductorlayer is formed. Then, a gate electrode is formed over the gateinsulating film, and the formation of a source region or a drain regionby doping to the semiconductor layer, the formation of an interlayerinsulating film (an inorganic insulating film), the formation of asource electrode or a drain electrode, activation treatment,hydrogenation treatment, and the like are appropriately performed,thereby manufacturing a top gate type TFT in which the polysilicon filmserves as the active layer. When phosphorus imparting n-typeconductivity is added as an impurity element for doping, an n-channelTFT can be formed. On the other hand, when boron imparting p-typeconductivity is added, a p-channel TFT can be formed. A CMOS circuit canbe manufactured by combining these TFTs.

Here, an example of a top gate type is shown as a structure of the TFT.However, the structure of the TFT is not limited and for example, thestructure may be a bottom gate type or a forward stagger type.

Various elements (a thin film diode; or a photoelectric transducerelement, a silicon resistance element, or a sensor element (typically, apressure-sensitive fingerprint sensor with the use of polysilicon)including a PIN junction of silicon) typified by a TFT can be formed byusing thus obtained semiconductor layer including a polysilicon film.

In this way, a peeling layer 103 including a circuit having an elementis formed (FIG. 1A).

In FIGS. 1A to 1F, the oxide film 102 and the peeling layer 103 areseparately shown. However, when peeling is performed, the oxide film 102can be included in one layer of the peeling layer, since the oxide film102 and the peeling layer 103 are integrated. In addition, the oxidefilm 102 is also referred to as a layer for protecting the peelinglayer.

Then, a protective layer 104 made of an adhesive material which issoluble in water or alcohols is applied to the entire surface, andbaked. The adhesive material may have any composition of, for example,epoxy series, acrylate series, silicon series, or the like. Here, aprotective layer made from a water-soluble resin (manufactured byTOAGOSEI Co., Ltd.: VL-WSHL10) is applied by spin coating to have a filmthickness of 30 μm, and is cured. The water-soluble resin film functionsas a planarizing film, which thereafter bonds a substrate so that asurface of the planarizing film and the surface of the substrate areplaced in parallel. In pressure-bonding, unevenness might occur due toan electrode or a TFT when the water-soluble resin film is not used.

Thereafter, a first two-sided tape 105 is pasted to the protective layer104 (FIG. 1B). It is preferable to paste the first two-sided tape 105under the reduced pressure in order to prevent a bubble from entering abonding face. Reference numeral 106 denotes a protective sheet of thetwo-sided tape 105, and the other bonding face of the two-sided tape canbe exposed by peeling the protective sheet in a later step.

Then, treatment to partially weakens adhesion of the metal film 101 tothe oxide film 102 is performed to make later peeling treatment easier,and treatment to remove a part of the substrate is further performed.The treatment to partially weaken adhesion is treatment to damage insideor a part of the interface of the oxide film 102 by locally applyingpressure from the outside along the periphery of a region to be peeled.For example, a scriber device which is moved by applying pressure with apress force ranging from 0.1 mm to 2 mm may be used. Afterwards, a partof the substrate is removed along a scribe line (FIG 1C).

Here, an example of a top view of the substrate is shown in FIG. 3A.FIG. 3A is an example in which nine CPUs are formed over one substrate,and reference numeral 301 denotes a substrate; 302, alignment markers;303, a metal film pattern; 304, circuit patterns; and 305, a portionwhere the substrate is removed. The alignment markers 302 are formed byetching the metal film pattern. Later peeling treatment is made easierby removing one side of the substrate as shown in FIG. 3A.

Then, a first fixing substrate 107 is pasted by peeling the protectivesheet 106 (FIG. 1D). It is preferable to paste the first fixingsubstrate 107 under the reduced pressure in order to prevent a bubblefrom entering a bonding face.

Then, a second fixing substrate 109 is pasted by a second two-sided tape108 (FIG. 1E). It is preferable to paste the second fixing substrate 109under the reduced pressure in order to prevent a bubble from entering abounding face. Note that the second fixing substrate 109 may not bepasted since it is pasted to protect the substrate 100 from beingcracked in later peeling treatment.

Subsequently, the first substrate 100 provided with the metal film 101 ais peeled with a physical means. The substrate can be peeled withrelatively small force (for example, human hands, wind pressure of a gasblown from a nozzle, ultrasonic waves, or the like). Here, peeling isconducted by pushing a wedge 110 in the part where a part of thesubstrate is removed. In this way, the peeling layer formed over thesilicon oxide layer 102 can be separated from the first substrate 100.FIG. 1F shows a state after peeling.

Incidentally, a direction 306 shown in FIG. 3A is desirably a directionfor peeling from the part where a part of the substrate is removed. Acircuit pattern 304 is not damaged even if a peeling defect is generateddue to the alignment markers 302 since the circuit pattern is notarranged in an extension of the peeling direction.

In order to eliminate a peeling defect due to the alignment marker, thealignment markers may be arranged as shown in FIG. 3B, and a part of thesubstrate where the alignment markers 312 are arranged may be furtherremoved before peeling in removing a part of the substrate. In FIG. 3B,three sides of the substrate are removed before peeling. In FIG. 3B,reference numeral 311 denotes a substrate; 312, alignment markers; 313,a metal film pattern; 314, circuit patterns; 315, a portion where thesubstrate is removed; and 316, a peeling direction.

The alignment markers in FIGS. 3A and 3B are openings which reach thesubstrate formed by etching the metal film pattern. When alignmentmarkers are formed to be openings which reach the oxide film, a peelingdefect due to the alignment markers can be prevented since the metalpattern is not etched.

Then, a second substrate 112 formed of a plastic film is bonded on theside of the oxide film 102 with an adhesive material 111 (FIG. 2A). Itis preferable to paste the second substrate 112 also under the reducedpressure in order to prevent a bubble from entering a bonding face. Asthe adhesive material 111, various kinds of curable adhesives such as areaction-cured adhesive, a thermo-setting adhesive, a photo-curableadhesive such as a UV-curable adhesive, an anaerobic adhesive can beused. As a material for the second substrate 112, a synthetic resinincluding polypropylene, polypropylene sulfide, polycarbonate,polyetherimide, polyphenylene sulfide, polyphenylene oxide, poly sulfoneor polyphtalamide can be used. An HT substrate with Tg of 400° C. ormore (manufactured by Nippon Steel Chemical Co., Ltd.) may be also used.

Subsequently, the first fixing substrate is separated from the firsttwo-sided tape (FIG. 2B). The first two-sided tape is then peeled (FIG.2C).

The resin layer formed of the water-soluble resin is dissolved andremoved by soaking in a solvent 113, here, water in a container 114(FIG. 2D).

Through the above-mentioned steps, the peeling layer provided over thefirst substrate can be transferred to the second substrate 112 formed ofthe plastic film with a preferable yield (FIG. 2E).

Moreover, another element may be formed over the transferred peelinglayer. For example, an anode, a layer containing an organic compound, alight emitting element having a cathode, a Schottky-type diode (a lightsensor) in which a photoelectric transducer layer is sandwiched betweenan anode electrode and a cathode electrode may be formed.

When gang printing is performed as shown in FIGS. 3A and 3B, eachcircuit pattern may be appropriately divided. A cutting process can beperformed comparatively easily compared with a glass substrate or aquartz substrate since it is cutting of a film substrate. When gangprinting is performed on a glass substrate or a quartz substrate, acrack or a chip is likely to occur with the use of a scriber device or abreaker device for cutting. Therefore, the smaller a circuit becomes,the more difficult a cutting process becomes. A cutting process can beeasily performed even if a circuit is small with laser processing, acutter, or the like since a film substrate is used in the invention.Hence, a large number of minute devices can be manufactured from alarge-sized substrate with a preferable yield.

EMBODIMENT MODE 2

Here, when an FPC is pressure-bonded to a device which is transferred toa flexible substrate such as a plastic film, a method for preventing adefect such as a crack and the like is shown with reference to FIGS. 4Ato 4C.

Initially, a peeling layer formed over a glass substrate is transferredto a flexible substrate according to Embodiment Mode 1. After forming ametal film over the glass substrate, at the time of forming an oxidefilm 404, a metal oxide film in an amorphous state is formed between themetal film and the oxide film. The peeling layer is then formed over theoxide film 404.

As the peeling layer to be transferred, a layer 405 a including acircuit having an element 405 a, and a terminal electrode 405 b areformed, and a protective layer 405 c formed from a resin to prevent acrack is formed thereover.

The metal oxide film becomes a crystallized metal oxide film 403 byperforming heat treatment of 400° C. or more in a process to form thepeeling layer.

According to Embodiment Mode 1, the glass substrate with the metal filmformed thereover is removed by separating at the interface between themetal oxide film 403 and the metal film, and the surface of the metaloxide film 403 is pasted to a flexible substrate 401 with a bondinglayer 402. FIG. 4A shows a cross-sectional view showing theabove-mentioned state and FIG. 4B shows a top view.

The terminal electrode 405 b is protected by being covered itscircumference with the resin 405 c. That is only a part of the electrodeface which is connected to an FPC is in an exposed state as FIG. 4Bshows an end portion 405 d of the resin.

Then, the electrode is connected by an aerotropic conductive film 406 byapplying pressure on the FPC 407 to bond (FIG. 4C). In thepressure-bounding step, a crack caused by deformation due to applicationof pressure can be prevented, since a wiring (a wiring connected to theterminal electrode) is protected by the resin 405 c.

In this specification, the aerotropic conductive film 406 means athermo-setting resin film or a thermoplastic resin film in which aconductive particle is mixed, and is also referred to as an ACF(anisotropic Conductive Film). The ACF may be either a two-layer ACF ora three-layer ACF. The FPC 407 is a film in which a wiring is providedover an insulating film and then laminated.

This embodiment mode can be freely combined with Embodiment Mode 1.

The following Embodiment describes the present invention formed of theabove-mentioned structure in further detail.

EMBODIMENT 1

In this embodiment, an example of transferring a semiconductorintegrated circuit, typically, a CPU to a plastic substrate is shown.FIG. 5A shows a cross-sectional view before transferring, and FIG. 5Bshows a cross-sectional view after transferring.

Initially, a metal layer 21 is formed over a thermostability substrate20 such as a quartz substrate or a glass substrate. In this embodiment,Corning 1737 (or EAGLE 2000) of 5 inches manufactured by CorningIncorporated is used as a glass substrate.

As a material forming the metal layer 21, an element of tungsten (W),molybdenum (Mo), technetium (Tc), rhenium (Re), ruthenium (Ru), osmium(Os), rhodium (Rh), iridium (Ir), palladium (Pd), and silver (Ag), analloy containing the element as its main component, or a monolayer orlamination layer of nitride (for example, titanium nitride, tungstennitride, tantalum nitride, or molybdenum nitride) can be used.

In this embodiment, the metal film 21, here, a tungsten film is formedby sputtering (under the deposition condition in which membrane stressis small: a flow of Ar, 100 sccm; a deposition pressure, 2 Pa; adeposition power, 4 kW; a substrate temperature, 200° C.; and a filmthickness, from 10 nm to 200 nm, preferably, from 50 nm to 75 nm) overthe glass substrate. Then, an oxide layer 12, here, a silicon oxide film(a film thickness of from 150 nm to 200 nm) is further laminated bysputtering without being exposed to the atmospheric air. The filmthickness of the oxide layer 12 is desirably twice or more of that ofthe metal layer. At the time of laminating, a metal oxide film (atungsten oxide film) in an amorphous state is formed with a thickness offrom 2 nm to 5 nm between the metal layer and the silicon oxide film.The metal oxide film in an amorphous state is shown by a dotted line inFIG. 5A. In peeling in a later step, peeling occurs inside the tungstenoxide film, at the interface between the tungsten oxide film and thesilicon oxide film, or at the interface between the tungsten oxide filmand the tungsten film. The tungsten oxide film remains on the surface ofthe oxide layer 12 after peeling, and it may be removed.

The tungsten film, the tungsten oxide film and the silicon oxide filmare formed also over an end face of the substrate with the use ofsputtering; therefore, it is preferable to selectively remove thesefilms by dry etching, O₂ ashing or the like.

Then, a silicon oxynitride film (a film thickness of 100 nm) whichserves as a base insulating film 13 is formed by PCVD, and an amorphoussilicon film containing hydrogen (a film thickness of 150 nm) is furtherlaminated without being exposed to the atmospheric air. Note that thesilicon oxynitride film is a blocking layer which prevents an impuritysuch as alkali metal from being diffused from the glass substrate. Inthis embodiment, a film thickness of the semiconductor film is made tobe relatively thick, since continuous oscillation laser light isradiated in a later step.

Thereafter, the above-mentioned amorphous silicon film is crystallizedby using a known technique (solid-phase growth, laser crystallization,crystallization using catalytic metal, or the like), and an elementusing a TFT having a polysilicon film as an active layer is formed.Here, the polysilicon film is obtained with crystallization usingcatalytic metal. A nickel acetate salt solution containing nickel of 10ppm by weight is applied with a spinner. A nickel element may be sprayedover the entire surface by sputtering instead of spin coating. Then,heat treatment is carried out to crystallize the amorphous silicon filmand to form a semiconductor film having a crystal structure (here, apolysilicon layer). In this embodiment, the silicon film having acrystal structure is obtained by performing heat treatment forcrystallization (at 550° C. for 4 hours) after another heat treatment(at 550° C. for one hour).

The amorphous silicon film contains hydrogen. In the case of forming apolysilicon film by heating, when heat treatment of 410° C. or more isperformed for crystallization, hydrogen can be diffused as well asforming the polysilicon film. The metal oxide film in an amorphous stateis crystallized by heat treatment of 410° C. or more; therefore, a metaloxide film having a crystal structure can be obtained. Accordingly, theheat treatment of 410° C. or more makes it possible to form the metaloxide film having a crystal structure; therefore, hydrogen is diffused.After the heat treatment of 410° C. or more is finished, the separationinside of the tungsten oxide film, or at the interface between thetungsten oxide film and the silicon oxide film, or at the interfacebetween the tungsten oxide film and the tungsten film can be achievedwith relatively small force (for example, human hands, wind pressure ofa gas blown from a nozzle, ultrasonic waves, or the like). Note that,when heat treatment is performed at a temperature at which the metaloxide film having a crystal structure can be obtained, the thicknessthereof is thinned to some extent as well as a change in a compositionof the metal oxide film. Further, the tungsten oxide film having acrystal structure has a plurality of crystal structures (WO₂, WO₃,WO_(x) (2<X<3)), and WO₃ is changed into WO₂, or WO_(x) depending on theheat treatment in its composition.

Then, after removing an oxide film on the surface of the silicon filmhaving a crystal structure with diluted hydrofluoric acid or the like,continuous oscillation laser light is radiated. It is preferable thatthe second harmonic through the fourth harmonic of fundamental waves isapplied by using a solid-state laser which is capable of continuousoscillation in order to obtain a crystal in a large grain size.Typically, it is preferable that the second harmonic (wavelength: 532nm) or the third harmonic (wavelength: 355 nm) of an Nd: YVO₄ laser(fundamental wave length: 1064 nm) may be applied. When continuous-wavelaser is used, laser light emitted from the continuous oscillation YVO₄laser with 10 W output is converted into a harmonic by using anon-linear optical element. Also, a method of emitting a harmonic byapplying a crystal of YVO₄ and a non-linear optical element into aresonator. Then, preferably, the laser light is formed to have arectangular shape or an elliptical shape on an irradiation face by anoptical system, thereby irradiating a substance to be treated. At thistime, the energy density of approximately from 0.01 MW/cm² to 100 MW/cm²(preferably from 0.1 MW/cm² to 10 MW/cm²) is required. The semiconductorfilm may be irradiated by being moved relatively to laser light with arate of approximately from 10 cm/s to 2000 cm/s.f

A barrier layer formed of an oxide film formed by treating the surfacewith ozone water for 120 seconds in addition to the oxide film formed bythe laser light irradiation, is formed with a thickness of from 1 nm to5 nm in total. The barrier layer is formed to remove nickel which isadded for crystallization from inside of the film. Though the barrierlayer is formed by using ozone water here, other methods such asultraviolet irradiation under the oxygen atmosphere or oxygen plasmatreatment to oxidize the surface of the semiconductor film having acrystal structure may be used. In addition, other method for forming thebarrier layer, an oxide film having a thickness of approximately from 1nm to 10 nm may be deposited by plasma CVD, sputtering, evaporation, orthe like. Note that before forming the barrier layer, the oxide filmformed by laser light irradiation may on the surface be removed.

Over the barrier layer, an amorphous silicon film containing an argonelement is formed to have a thickness of from 10 nm to 400 nm, in thisembodiment, 50 nm by sputtering to serve as a gettering site. In thisembodiment, the amorphous silicon film containing argon is formed underan atmosphere containing argon by using a silicon target. When plasmaCVD is used for forming the amorphous silicon film containing an argonelement, it is formed under the deposition condition where a flow ratioof monosilane to argon (SiH₄ to Ar) is 1/99; a pressure duringdeposition, 6.665 Pa (0.05 Torr); an RF power density, 0.087 W/cm²; anda deposition temperature, 350° C.

Then, a furnace heated at 550° C. is used for heat treatment for 4 hoursfor gettering to reduce the nickel concentration in the semiconductorfilm having a crystal structure. A lamp annealing apparatus may be usedinstead of the furnace Subsequently, the amorphous silicon filmcontaining an argon element, which is the gettering site, is selectivelyremoved by using the barrier layer as an etching stopper, and then, thebarrier layer is selectively removed with diluted hydrofluoric acid.Note that there is a tendency that nickel is likely to move to a regionhaving a high oxygen concentration in gettering, and thus, it isdesirable that the barrier layer formed of the oxide film is removedafter gettering.

Then, after a thin oxide film is formed from ozone water on the surfaceof the obtained silicon film having a crystal structure (also referredto as a polysilicon film), a mask made from a resist is formed with theuse of a first photomask, and etching treatment is conducted thereto toobtain a desired shape, thereby forming island-like semiconductor layersseparated from one another. After forming the semiconductor layers, themask made from a resist is removed.

Then, doping of a small amount of impurity element (boron or phosphorus)is performed in order to control the threshold value of the TFT, ifnecessary. Here, ion doping in which plasma is excited is used withoutperforming mass separation on diborane (B₂H₆).

Next, the oxide film is removed with an etchant containing hydrofluoricacid, and at the same time, the surface of the silicon film is washed.Thereafter, an insulating film containing silicon as its main component,which serves as a gate insulating film, is formed. In this embodiment, asilicon oxynitride film (composition ratio: Si=32%, O=59%, N=7%, H=2%)is formed to have a thickness of 115 nm by plasma CVD.

Then, after forming a metal film over the gate insulating film,patterning is performed with the use of a second photomask, therebyforming a gate electrode (or gate wiring) and a terminal electrode.Then, a source region or a drain region of a TFT is formed by dopinginto an activated layer.

Then, after a first interlayer insulating film formed of a silicon oxidefilm is formed to have a thickness of 50 nm by CVD, a step of treatmentfor activating the impurity elements added into each semiconductor layeris performed. The activation step is performed by rapid thermalannealing with the use of a lamp light source (RTA), a method forradiating a YAG laser or an excimer laser from a back side, heattreatment using a furnace, or a method in which any of the steps arecombined.

Then, a second interlayer insulating film formed of a silicon nitrideoxide film containing hydrogen is formed, and heat treatment (for from 1hour to 12 hours at temperatures from 300° C. to 550° C.) is performedto conduct a step of hydrogenating the semiconductor layer. This step isa step of terminating a dangling bond by hydrogen contained in the firstinsulating film. The semiconductor layer can be hydrogenated regardlessof the interlayer insulating film formed of the silicon oxide film.

Then, a third interlayer insulating film including an organic insulationmaterial is formed over the second interlayer insulating film. Here, anacrylic resin film with a film thickness of 0.8 μm is formed.

A fourth interlayer insulating film formed of an inorganic insulatingfilm having a film thickness of from 250 nm to 350 nm is formed over thethird interlayer insulating film by sputtering.

Then, a mask made from a resist is formed with the use of a thirdphotomask, and a contact hole is formed by selectively etching theinterlayer insulating film or the gate insulating film. Thereafter, themask formed from a resist is removed.

Subsequently, a mask formed from a resist is fromed with the use of afourth photomask after laminating a metal film, and a source electrodeor a drain electrode of a TFT is formed by selectively etching the metallaminated film. Then, the mask formed from a resist is removed. Inaddition, the metal laminated film is a three-layer lamination of a Tifilm with a film thickness of 100 nm, an Al film which contains a smallamount of Si with a film thickness of 350 nm, and a Ti film with a filmthickness of 100 nm.

Through the above-mentioned steps, a top gate type TFT 15 which uses thepolysilicon film as the active layer can be manufactured.

Then, a fifth interlayer insulating film made of a an inorganicinsulating film or an organic resin is formed. After a contact hole isformed by etching the fifth interlayer insulating film, a connectionwiring or a terminal electrode made from a metal material is formed. ACMOS circuit 16 in which a p-channel TFT and an n-channel TFT arecombined is manufactured by forming the connection wiring.

Incidentally, as each interlayer insulating film (the first interlayerinsulating film to the fifth interlayer insulating film), an inorganicmaterial (silicon oxide, silicon nitride, silicon oxynitride or thelike), a photosensitive or non-photosensitive organic material(polyimide, acrylic, polyamide, polyimidamide, resist orbenzocyclobutene), an SOG film obtained by spin coating (for example, anSiOx film containing an alkyl group), or a lamination thereof can beused.

Then, a protective layer 14 is formed, and only a terminal portion 17 isexposed by selectively etching the protective layer 14. The protectivelayer 14 is provided to prevent a crack due to pressure-bonding inmounting an FPC. FIG. 5A shows a cross-sectional view after theabove-mentioned steps.

As the protective layer 14, a photosensitive or non-photosensitiveorganic material (polyimide, acrylic, polyamide, polyimidamide, resistor benzocyclobutene), an SOG film obtained by spin coating (for example,an SiOx film containing an alkyl group in which a siloxane applicationfilm is used, or an SiOx film in which a polysilazane application filmis used), or a lamination thereof can be used.

Then, an adhesive material which is soluble in water or alcohols isapplied to the entire surface, and baked. The adhesive material may haveany composition of, for example, epoxy series, acrylate series, siliconseries, or the like. Here, a film made from a water-soluble resin(manufactured by TOAGOSEI Co., Ltd.: VL-WSHL10) is applied by spincoating to have a film thickness of 30 μm, and is exposed for twominutes to be temporarily cured, then, exposed its back to UV rays for2.5 minutes, and its surface for 10 minutes to be fully cured. Thewater-soluble resin film serves as a planarizing film, which thereafterbonds a substrate so that a surface of the planarizing film and thesurface of the substrate are placed in parallel. Unevenness might occurdue to an electrode or a TFT when the water-soluble resin film is notused in pressure-bonding a first fixing substrate.

Then, a first two-sided tape is pasted to an adhesive material.

Treatment of partially weakening the adhesion between the metal layerand the metal oxide film, or the metal oxide film and the oxide film isperformed for easy separation. The treatment for partially wakening theadhesion is carried out by using a scriber device which is moved withapplying pressure with a press force ranging from 0.1 mm to 2 mm. Then,a part of the glass substrate may be cut off with a breaker device.

Then, the first fixing substrate made of a quartz substrate is fixed tothe first two-sided tape. Next, a second fixing substrate is fixed underthe glass substrate with a second two-sided tape.

Then, peeling is performed from a side where a part of the glasssubstrate is removed, and the glass substrate 20 over which the metallayer 21 is provided is peeled with a physical means. The glasssubstrate 20 can be peeled with relatively small force (for example,human hands, wind pressure of a gas blown from a nozzle, ultrasonicwaves, or the like). Thus, the peeling layer formed over the oxide layercan be separated from the glass substrate 20.

After peeling, one third of WO₃ remains over the glass substrate and thetwo thirds remains over the side of the peeling layer. Peeling is likelyto occur inside the tungsten oxide film, especially, at the interfacebetween WO₂ and WOx, or at the interface between WO₂ and WO₃. Althoughthe tungsten oxide film partially remains over the side of the peelinglayer, it is not matter if the tungsten oxide film is removed or notremoved since the film is transparent.

Then, a film substrate 10 and the oxide layer 12 (and the peeling layer)are bonded together with an adhesive material 11. It is important thatadhesion between the first fixing substrate and the peeling layer by thefirst two-sided tape is higher than that of between the oxide layer 12(and the peeling layer) and the film substrate 10.

Then, the first fixing substrate is separated from the first two-sidedtape. Next, the two-sided tape is peeled. Further, the water-solubleresin is dissolved and removed with the use of water.

Through the above-mentioned steps, the TFT 15 and the CMOS circuit 16which are transferred to the film substrate 10 can be formed (FIG. 5B).In this embodiment, a CPU is designed with the use of these elements.

Cross-sectional photographs of a TFT which is actually transferred to afilm substrate taken by a SEM is shown in FIGS. 6 and 7. FIG. 7 is anenlarged view of FIG. 6. A TFT having a single drain structure with agate length of 1.2 μm can be confirmed with reference to FIG. 7.

In this embodiment, approximately 27,000 TFTs are used to configure aCPU, and a layout having 10 mm² of chip area is achieved. As shown inFIG. 8, 12 chips can be formed in a substrate of 5 inches.

FIG. 9 shows a photograph of one chip on which an FPC is pressure-bondedafter division of the substrate. An FPC can be mounted without causingany disconnection defect such as a crack even when the FPC ispressure-bonded since the protective layer 14 is provided.

FIG. 10 shows a block diagram of one chip and is describes hereinafter.

When an opecode is inputted into an interface 1001, the code isdecrypted in an analysis unit 1003 (also referred to as an InstructionDecoder), and a signal is inputted into a control signal generation unit1004 (a CPU Timing Control). When the signal is inputted, a controlsignal is outputted from the control signal generation unit 1004 to anarithmetic logical unit 1009 (hereinafter, an ALU) and a memory unit1010 (hereinafter, a Register).

The control signal generation unit 1004 includes an ALU controller 1005for controlling the ALU 1009 (hereinafter, an ACON), a unit 1006 forcontrolling the Register 1010 (hereinafter, a RCON), a timing controller1007 for controlling timing (hereinafter, a TCON), and an interruptioncontroller 1008 for controlling interruption (hereinafter, an ICON).

On the other hand, when an operand is inputted into the interface 1001,the operand is outputted to the ALU 1009 and the Register 1010. Then, aprocessing based on a control signal, which is inputted from the controlsignal generation unit 1004 (for example, a memory read cycle, a memorywrite cycle, an I/O read cycle, an I/O write cycle, or the like), iscarried out.

The Register 1010 includes a general resister, a stack pointer (an SP),a program counter (a PC), and the like.

An address controller 1011 (hereinafter, an ADRC) outputs 16 bitsaddress.

A structure of the CPU described in this embodiment is an example of aCPU manufactured according to the present invention and does not limitthe structure of the invention. Therefore, it is possible to use a knownstructure of a CPU other than that shown in this embodiment.

Note that a graph shown in FIG. 11 is current characteristics of ann-channel TFT and a p-channel TFT having 1.2 mm of a gate length and 20mm of a gate width. The n-channel TFT has a threshold voltage of 0.8 V;an S value, about 0.16 V/dec; a drain current, about 27 mA/mm (Vgs=3.3V, Vds=1 V), while the p-channel TFT has a threshold voltage of 0.6 V;an S value, about 0.14 V/dec; a drain current, about 16 mA/mm (Vgs=−3.3V, Vds=−1 V). Thus, a TFT with high properties can be achieved.

FIG. 12 shows the result of evaluation of the obtained CPU (a shmoo plotof a chip). Movement in an operation frequency of 13 MHz in a powersupply voltage of 3.3 V is confirmed with reference to FIG. 12. Inaddition, with reference to FIG. 12, it is assumed that operationproperties of a chip according to this embodiment is sufficiently withinthe range of practical use as an LSI for a relatively easy built-intype.

In this embodiment, a TFT having a single drain structure is explained.However, an LDD may be provided if necessary, or a multi-gate TFT havinga plurality of channel formation regions, for example, a double gate TFTmay be used.

This embodiment can be freely combined with Embodiment Mode 1 orEmbodiment Mode 2.

EMBODIMENT 2

In this embodiment, an example of manufacturing a light emitting devicein which light emitting elements having a layer containing an organiccompound are arranged in matrix is described.

Initially, an element is formed over a glass substrate (a firstsubstrate 300). In this embodiment, AN100 manufactured by Asahi GlassCo., Ltd. is used as a glass substrate. A metal film 1301 a and an oxidefilm 1302 are laminated over the substrate by sputtering same asEmbodiment 1. In laminating, a metal oxide film (a tungsten oxide film)in an amorphous state is formed between the metal film 1301 a and thesilicon oxide film 1302 in approximately from 2 nm to 5 nm thick.

Then, the metal film, the metal oxide film, and the silicon oxide filmwhich are formed at the edge face of the substrate are selectivelyremoved by O₂ ashing or the like.

Then, a silicon oxynitride film (a film thickness of 100 nm) whichserves as a base insulating film is formed by PCVD, and an amorphoussilicon film containing hydrogen (a film thickness of 54 nm) is furtherlaminated without being exposed to the atmospheric air.

Then, a TFT 1303 in which a polysilicon film serves as an active layeris formed by crystallizing the above-mentioned amorphous silicon film bya known technique (solid-phase growth, laser crystallization,crystallization using catalytic metal, or the like).

Then, a film containing an organic compound (hereinafter, referred to asan organic compound layer) is provided between a pair of electrodes (ananode and a cathode), and a light emitting element in which fluorescenceor phosphorescence can be obtained by applying electric field betweenthe pair of the electrodes is formed. Initially, a first electrode 1304which serves as an anode or a cathode is formed. Here, an example inwhich a metal film having a high work function (Cr, Pt, W or the like),or a transparent conductive film (ITO (indium oxide tin oxide alloy),indium oxide zinc oxide alloy (In₂O₃—ZnO), zinc oxide (ZnO) or the like)is used as the first electrode 1304 and is functioned as an anode, isshown.

When the first electrode 1304 is used as the anode, it is preferablethat the TFT 1303 is a p-channel TFT. In the case of connecting with thep-channel TFT, the TFT is connected with the anode, and aftersequentially laminating a hole injecting layer/a hole transportinglayer/a light emitting layer/an electron transporting layer over theanode, a cathode may be formed. In the case of connecting with then-channel TFT, the TFT is connected with the cathode, and aftersequentially laminating an electron transporting layer/a light emittinglayer/a hole transporting layer/a hole injecting layer over the cathode,an anode may be formed.

When a source electrode or a drain electrode of a TFT serves as a firstelectrode, or a first electrode in contact with a source region or adrain region is formed separately, the TFT includes the first electrode.

A partition wall (also referred to as a bank, a barrier or the like)1305 a is formed on the both ends of the first electrode (anode) so asto encircle the periphery of the first electrode. To improve thecoverage, the upper edge portion or the bottom edge portion of thepartition wall is formed to have a curved surface having curvature. Forexample, in the case that a positive type photosensitive acrylic is usedas a material for the partition wall, it is preferable that only theupper edge portion of the partition wall is formed to have a curvedsurface having radius of curvature (from 0.2 μm to 3 μm). Either anegative type that is insoluble in etchant according to light having awavelength in which photosensitive acrylic reacts or a positive typethat is dissoluble in etchant according to the light can be used aspartition wall.

Further, in the case of laminating a plurality of organic resins, thereis a possibility that the plurality of organic resins is partiallymelted at the time of applying or baking, or the plurality of organicresins are too adhesive between the organic resins depending on a usedsolvent. Therefore, in the case of using an organic resin as a materialfor the partition wall, the partition wall 1305 a is preferably coveredwith an inorganic insulating film (an SiN_(x) film, an SiN_(x)O_(y)film, an AlN_(x) film, or an AlN_(x)O_(y) film) in order to make it easyto remove the water-soluble resin after coating it in a later step. Theinorganic insulating film serves as a part of the partition wall 1305 b(FIG. 13A).

Next, an adhesive material 1306 that is soluble in water or alcohols iscoated over the entire surface and baked (FIG. 13B).

Then, after pasting a two-sided tape 1307 to the adhesive material 1306,treatment for partially weakening adhesion between the metal film 1301 aand the metal oxide film 1301 b, or between the metal oxide film 1301 band the oxide film 1302 is performed. Here, one side of the substrate iscut off with a CO₂ laser.

Then, a second substrate 1308 is pasted to the two-sided tape 1307.Further, a third substrate 1310 is pasted to the first substrate 1300with the use of a two-sided tape 1309 (FIG. 13C).

Then, peeling is performed from a region where the adhesion is partiallyweakened. A state after peeling is shown in FIG. 13D.

Then, a fourth substrate 1312 and the oxide layer 1302 (and a peelinglayer) are adhered together with an adhesive material 1311 (FIG. 13E).

A plastic substrate (ARTON made from a norbornene resin having a polargroup, manufactured by JSR Corporation) is used for the fourth substrate1312. In addition, a plastic substrate such as polyethyleneterephthalate (PET), polyethersulfone (PES), polyethylene naphthalate(PEN), polycarbonate (PC), nylon, polyetheretherketone (PEEK),polysulfone (PSF), polyetherimide (PEI), polyarylate (PAR), polybutyleneterephthalate (PBT), or polyimide can be used.

Then, the second substrate 1308 is separated from the two-sided tape1307 (FIG. 13F).

Then, the two-sided tape 1307 is peeled (FIG. 13G).

Then, the adhesive material 1306 is dissolved and removed with the useof a solvent (FIG. 13H). If the adhesive material 1306 remains, itcauses a defect. Therefore, it is preferable to make the surface of thefirst electrode 1304 clean with washing treatment or O₂ plasmatreatment.

Then, the surface of the first electrode 1304 is rubbed and washed witha porous sponge (typically a sponge made of PVA (polyvinyl alcohol), ornylon) soaked in a surface-active agent (weak alkaline), if necessary.

Then, the substrate provided with the TFT and the partition wall isheated in vacuum for removing absorbed moisture in the entire substrate,right before forming a layer 1313 containing an organic compound.Further, the first electrode may be irradiated with ultraviolet rayright before forming the layer 1313 containing an organic compound.

Then, the layer 1313 containing an organic compound is selectivelyformed over the first electrode (the anode) by vapor deposition with theuse of an evaporation mask or ink-jetting. As the layer 1313 containingan organic compound, a layer made from a high molecular weight material,low molecular weight material, an inorganic material, a mixed layerformed of these materials, a layer formed by dispersing these materials,or a lamination formed by appropriately combining these layers may beused.

Moreover, a second electrode (cathode) 1314 is formed over the layercontaining an organic compound (FIG. 131). As the cathode 1314, alamination layer of a thin film, which has a film thickness enough to betransparent to light, formed of a material having a low work function(Al, Ag, Li, Ca, an alloy of these: MgAg, MgIn, AlLi, or a compound ofthese: CaF₂ or CaN) and a transparent conductive film may be used. Inaddition, a protective layer is formed to cover the second electrode bysputtering or vapor deposition, if necessary. As the protective layer, asilicon nitride film, a silicon oxide film, a silicon oxynitride film (aSiNO film: a ratio of N to O composition is N>O), or a SiON film (aratio of N to O composition is N<O), or a thin film containing carbon asits main component (for example, a DLC film or a CN film), obtained bysputtering or CVD can be used.

A sealing material (not shown) containing a gap material for maintaininga gap between a pair of substrates is applied to a fifth substrate 1314that serves as a sealing member. The fifth substrate 1314 may be alight-transmitting substrate in this embodiment since an example of thelight emitting element in which light generated therein emits throughthe fifth substrate 1314 is described. Here, the same plastic substrateas the fourth substrate (ARTON, manufactured by JSR Corporation) is usedto prevent a warp by equalizing the thermal expansion coefficient. TheARTON substrate is suitable for the fifth substrate since it is hardlybirefringent and has a low water absorption rate. When a plasticsubstrate is used, it is preferable that a pretreatment for improvingthe adhesion between the plastic substrate and the sealing material isperformed before a pattern of the sealing material (ethanol wiping,ultraviolet ray radiation, O₂ plasma treatment or the like) is drawn.

Thereafter, a few drops of sealing material with a low viscosity aredropped to paste the sealing substrate and an active matrix substratewith each other without generating air bubbles using a vacuum pastingdevice. The vacuum pasting device is of use particularly when a pair offlexible plastic substrates is pasted together. Moreover, a method forapplying a few drops of the sealing material with low viscosity is alsoof use for pasting a pair of flexible substrates together. With thispasting step, sealing is performed in a manner where a light emittingregion provided over an active matrix substrate is surrounded by sealingpatterns provided over a sealing substrate. Further, sealing isperformed in a manner where a space surrounded by the sealing materialis filled with an adhesive material 315 formed from a transparentorganic resin (FIG. 13J).

Through the above-mentioned steps, a light emitting device provided witha TFT and a light emitting element can be manufactured with plasticsubstrates 1312 and 1314 serving as holders. Since the holders areplastic substrates, the light emitting device can be thin, lightweightand flexible.

In the light emitting device of this embodiment, a method for drivingscreen display is not specifically limited, and a dot sequential drivesystem, a line sequential drive system, a area sequential drive systemor the like may be employed. Typically, the line sequential drive systemis employed, and a time division gradation sequence drive system or anarea gradation drive system may be utilized as needed. The video signalto be inputted into a source line of the light emitting device may beeither an analogue signal or a digital signal, and the drive circuit orthe like may be appropriately designed corresponding to the videosignal.

Further, in a light emitting device using a digital video signal, thereare two kinds of video signals inputted into a pixel: a signal withconstant voltage (CV) and a signal with constant current (CC). Further,as for the video signal with constant voltage (CV), there are two kinds:a signal in which voltage applied to a light emitting element isconstant (CVCV), and a signal in which current applied to a lightemitting element is constant (CVCC). In addition, as for the videosignal with constant current (CC), there are two kinds: a signal inwhich voltage applied to a light emitting element is constant (CCCV),and a signal in which current applied to a light emitting element isconstant (CCCC).

In the light emitting device of this embodiment, a protective circuitfor preventing electrostatic discharge damage (a protective diode) maybe provided.

This embodiment can be freely combined with any one of Embodiment Mode1, Embodiment Mode 2, or Embodiment 1.

EMBODIMENT 3

Various types of modules (an active matrix type EL module, a passivematrix type EL module, a liquid crystal display device, and an activematrix type EC module) can be completed by according to the presentinvention. In other words, electronic devices in all fields which mountthe modules can be completed according to the invention.

Examples of these kinds of electronic devices are as follows: a videocamera; a digital camera; a head mounted display (a goggle typedisplay); a car navigating system; a projector; a mobile stereo; apersonal computer; a card; a personal digital assistant (a mobilecomputer, a cellular phone, an electronic book, and the like). FIGS. 14Ato 14C show one example thereof.

FIG. 14A illustrates a cellular phone which includes a main body 2901,an audio output portion 2902, an audio input portion 2903, a displayportion 2904, operation switches 2905, an antenna 2906, an image inputportion (CCD, an image sensor, and the like) 2907, and the like. Thedisplay portion can be made thinner according to the inventiontransferred to a plastic substrate. Consequently, the total weight ofthe cellular phone can be made lightweight. In the display portion withthe use of a plastic substrate, durability against the impact in fallingcan be enhanced.

FIG. 14B illustrates a card or a card type personal digital assistantwhich includes a display portion 3011, a driver circuit portion 3013, afunctional circuit portion 3012 such as a CPU, a seal pattern 3014, abattery 3015, and a flexible substrate 3010. Although a mode in whichtwo flexible substrates are sandwiched in FIG. 14B, the display portion3011, the driver circuit portion 3013, the functional circuit portion3102 such as a CPU may be provided over one flexible substrate. Theweight of the personal digital assistant can be made lightweight sincethe personal digital assistant can be made wholly thinner according tothe invention in which various functional circuits are transferred to aplastic substrate. Peeling and transferring to a plastic substrate maybe performed by forming a functional circuit portion such as a displayportion and a CPU over one glass substrate. Alternatively, a functionalcircuit portion such as a display portion and a CPU is separately formedover different glass substrates, and transferring to one plasticsubstrate may be performed after peeling.

FIG. 14C illustrates a lap-top personal computer, which includes a mainbody 3201, a casing 3202, a display portion 3203, a keyboard 3204, anexternal connection port 3205, a pointing mouse 3206 and the like. Thedisplay portion 3203 can be made thinner according to the inventiontransferred to a plastic substrate. According to the invention, a CPU(not shown) can be provided over a plastic substrate resulting inactualizing lightweigh. In the display portion with the use of a plasticsubstrate, durability against the impact in falling can be enhanced.

As described above, a semiconductor device obtained according to theinvention can be used as a part of any electronic devices. Note that asemiconductor device manufactured by using any configuration ofEmbodiment Mode 1, Embodiment Mode 2, Embodiment 1 or Embodiment 2 canbe applied to the electronic devices in this embodiment.

According to the invention, peeling, transferring and mounting can berealized with a preferable yield, even when gang printing is performedwith the use of a substrate having a large area.

According to the invention, gang printing can be performed over a filmsubstrate. Accordingly, a cutting process to obtain a small-size circuitpattern can be performed easily with laser processing, a cutter, or thelike. Therefore, a large number of minute devices can be manufacturedwith a preferable yield from a large-size substrate.

1. A method for manufacturing a semiconductor device, comprising thesteps of: forming a peeling layer containing an element over a firstsubstrate; applying an organic resin film which can be dissolved in asolvent over the peeling layer containing an element; pasting a firsttwo-sided tape over the organic resin film; cutting off and removing apart of the first substrate; pasting a second substrate to the firsttwo-sided tape; pasting a third substrate under the first substrate witha second two-sided tape; performing peeling to separate the firstsubstrate, the second two-sided tape, and the third substrate from thepeeling layer; pasting a fourth substrate to the peeling layer with anadhesive material.
 2. A method for manufacturing a semiconductor device,comprising the steps of: forming a peeling layer containing an elementand an alignment marker over a first substrate; forming an organic resinfilm which can be dissolved in a solvent over the peeling layercontaining an element; pasting a first two-sided tape over the organicresin film; cutting off and removing a part of the first substrate whichis overlapped with the alignment marker; pasting a second substrate tothe first two-sided tape; pasting a third substrate under the firstsubstrate with a second two-sided tape; performing peeling to separatethe first substrate, the second two-sided tape, and the third substratefrom the peeling layer; pasting a fourth substrate to the peeling layerwith an adhesive material.
 3. A method for manufacturing a semiconductordevice according to claim 1 or claim 2, wherein the second substrate andthe third substrate have higher rigidity than that of the firstsubstrate, and the fourth substrate is a film substrate.
 4. A methodaccording to claim 1 or 2, wherein said peeling is performed from a partwhere the part of the first substrate is cut off and removed.
 5. Amethod according to claim 1 or 2, further comprising steps of: removingthe second substrate; removing the first two-sided tape; and removingthe organic resin film by dissolving with a solvent.
 6. A methodaccording to claim 1 or 2, wherein said element is a TFT element.
 7. Amethod according to claim 1 or 2, wherein said semiconductor device isone selected from the group consisting of a personal computer, a card,and a cellular phone.
 8. A method for manufacturing a semiconductordevice, comprising the steps of: forming a peeling layer containing anelement over a first substrate; forming an organic resin film which canbe dissolved in a solvent over the peeing layer containing an element;pasting a two-sided tape over the organic resin film; cutting off andremoving a part of the first substrate; pasting a second substrate tothe two-sided tape; performing peeling to separate the first substratefrom the peeling layer; pasting a third substrate to the peeling layerwith an adhesive material.
 9. A method for manufacturing a semiconductordevice according to claim 8, wherein the second substrate has higherrigidity than that of the first substrate, and the third substrate is afilm substrate.
 10. A method according to claim 8, wherein said peelingis performed from a part where the part of the first substrate is cutoff and removed.
 11. A method according to claim 8, further comprisingsteps of: removing the second substrate; removing the first two-sidedtape; and removing the organic resin film by dissolving with a solvent.12. A method according to claim 8, wherein said element is a TFTelement.
 13. A method according to claim 8, wherein said semiconductordevice is one selected from the group consisting of a personal computer,a card, and a cellular phone.
 14. A method for manufacturing asemiconductor device, comprising the steps of: forming a peeling layercontaining an element and a terminal electrode over a first substrate;peeling the peeling layer and a terminal electrode from the firstsubstrate; pasting a second substrate to the peeling layer and aterminal electrode with an adhesive material; and pressure-bonding anFPC to a terminal electrode in which a circumference is covered with aresin.
 15. A method for manufacturing a semiconductor device accordingto claim 14, wherein the first substrate is a glass substrate and thesecond substrate is a film substrate.
 16. A method according to claim14, wherein said element is a TFT element.
 17. A method according toclaim 14, wherein said semiconductor device is one selected from thegroup consisting of a personal computer, a card, and a cellular phone.